A new approach to study viral induced membrane change in productive and non-productive SSPE infection has been developed in vitro. It consists in immunolabeling combined with freeze-fracturing, deep-etching and surface replication. It brings extensive and meaningful information on viral events occurring both inside the membrane and on the true outer surface in productive and non-protective cells. The spatial organization and distribution of viral antigen in cells infected with different strains of measles virus can now be precised.